50" Samsung Plasma (model number PS50Q91HD) - possible purchase

[psmedley]

Re: 50" Samsung Plasma (model number PS50Q91HD) - possible purchase

Well my 1SS184 diodes arrived today - got them installed, but can't test it out yet as I had removed to 20 ohm and 10k ohm smd resistors for testing, and in the process or replacing them I busted one 20 ohm resistor and lost another one. Fortunately, I had already ordered replacements which should be here any day now!

[tom66]

Re: 50" Samsung Plasma (model number PS50Q91HD) - possible purchase

Before you blow some more FETs test it with a 100W light bulb in series...

[randtek]

Re: 50" Samsung Plasma (model number PS50Q91HD) - possible purchase

FYI, When you first replaced the Mosfets, probably the reason they failed while you were away from the set is that Samsungs remember the current power on setting. If unit was on when it failed, as soon as standby power comes up, unit will attempt to turn itself on. It probably turned on while you were away from the set and blew the mosfets.

[retiredcaps]

Re: 50" Samsung Plasma (model number PS50Q91HD) - possible purchase

Well my 1SS184 diodes arrived today

From the USA or Thailand?

[psmedley]

Re: 50" Samsung Plasma (model number PS50Q91HD) - possible purchase

Before you blow some more FETs test it with a 100W light bulb in series...

Can you explain more on where exactly the wire in the bulb?

[psmedley]

Re: 50" Samsung Plasma (model number PS50Q91HD) - possible purchase

From the USA or Thailand?

USA - mailed on 29th June, arrived 9th July - 10 days - not bad for the USPS

[psmedley]

Re: 50" Samsung Plasma (model number PS50Q91HD) - possible purchase

FYI, When you first replaced the Mosfets, probably the reason they failed while you were away from the set is that Samsungs remember the current power on setting. If unit was on when it failed, as soon as standby power comes up, unit will attempt to turn itself on. It probably turned on while you were away from the set and blew the mosfets.

blew as they weren't secured to the heatsink, so overheated?

[retiredcaps]

Re: 50" Samsung Plasma (model number PS50Q91HD) - possible purchase

Can you explain more on where exactly the wire in the bulb?

https://www.badcaps.net/forum/showpo...07&postcount=7

[retiredcaps]

Re: 50" Samsung Plasma (model number PS50Q91HD) - possible purchase

USA - mailed on 29th June, arrived 9th July - 10 days - not bad for the USPS

That is really good considering that includes the July 4th holiday. One of my ebay orders from the USA has been stuck in the sorting facility for 5 days now due to the July 4th holiday. :-(

[psmedley]

Re: 50" Samsung Plasma (model number PS50Q91HD) - possible purchase

https://www.badcaps.net/forum/showpo...07&postcount=7

OK - I also read http://smpstroubleshooting.com/power...oting-secrets/

This power supply has two fuses though, F801 immediately adjacent to the AC input, and F803 which is near the mosfets that I found blown.

I also read about failed startup caps causing high voltages and blown parts, so I'm thinking that as I have replacements, I'll replace all the caps I can on the hot side of the power supply.

[tom66]

Re: 50" Samsung Plasma (model number PS50Q91HD) - possible purchase

Can you explain more on where exactly the wire in the bulb?

In series with Live/Active. The bulb will light if a short persists.

[scokljat]

Re: 50" Samsung Plasma (model number PS50Q91HD) - possible purchase

I found this thread (and some other) so exciting and tense like a good book ;-) What will happen next? Who is the bad guy, victim or the killer?! We have some usual suspects here, lot of victims, actually it's double murder for now. Clues are scattered all over 50 inch crime scene!! Maybe it's time to call fancy CSI chicks to take a look ;-)

Well, I hope it will be a happy ending. I'm also waiting for IPM delivery for my 42" repair from other thread. It usually takes 15-30 days for stuff to come to Croatia... It will be a long wait. Till then, I wish you luck!

Cheers!

Suad

[psmedley]

Re: 50" Samsung Plasma (model number PS50Q91HD) - possible purchase

In series with Live/Active. The bulb will light if a short persists.

Hmm 100w incandescent light bulbs are like hens teeth here - would a 72W halogen 240v globe suffice?

[psmedley]

Re: 50" Samsung Plasma (model number PS50Q91HD) - possible purchase

Oh, and once I find a 100W globe, when I power it up, should I have all the sub-boards connects to the power supply?

[tom66]

Re: 50" Samsung Plasma (model number PS50Q91HD) - possible purchase

Oh, and once I find a 100W globe, when I power it up, should I have all the sub-boards connects to the power supply?

Everything should be connected and try to turn the TV on though I'd expect the TV to not power on properly with the bulb in series, but it will prevent a short from causing more issues.

[psmedley]

Re: 50" Samsung Plasma (model number PS50Q91HD) - possible purchase

Everything should be connected and try to turn the TV on though I'd expect the TV to not power on properly with the bulb in series, but it will prevent a short from causing more issues.

Thanks Tom - I'll assume that if I can't find a 100W globe, that two globes in series adding up to 100W would suffice?

[tom66]

Re: 50" Samsung Plasma (model number PS50Q91HD) - possible purchase

Thanks Tom - I'll assume that if I can't find a 100W globe, that two globes in series adding up to 100W would suffice?

That should be fine, just make sure not to use anything with an electronic or magnetic ballast, you -must- use an incandescent or halogen bulb.

[tom66]

Re: 50" Samsung Plasma (model number PS50Q91HD) - possible purchase

Thinking about it, it might be better to use two 50W in parallel, or equivalent. You can use less, but you can't be sure the PSU will even start up into standby.

[psmedley]

Re: 50" Samsung Plasma (model number PS50Q91HD) - possible purchase

OK it's all back together... just gotta try find a suitable globe on the way home from work tomorrow before I fire it up

Took the opportunity to replace a bunch of shitty samyoung caps with rubycons too

[psmedley]

Re: 50" Samsung Plasma (model number PS50Q91HD) - possible purchase

Found a 100W spotlight Unfortunately, when I turn the TV on I get relay clicking and the light flashes on/off inline with the relay.

The fuse for the mosfets is still good.

Ideas?